No feedback on taking of R1737.15 from my account

I bought a 3G day and 4G data contract at Woodlands Cell C on 20 Oct 15 .I paid R195 action fee. I signed a debit order for 15th of each month from 15 Nov 15. On 1 Nov 15(after 10days of the contract signature) I received an invoice for R1735.15.I visited Woodlands branch three times to try and establish what this was for but eventually was told to phone the Technical Department of Cell C myself at ***. I tried several times but was cut off before I could speak to anybody. I contacted Cell during my night surfing 4G(because I had no signal during the day) and they sent me a reference number, ID 75590, and promised to contact me on or before 18 Nov 15. Nothing happened except that they took R1735.15 from my bank account on 15 Nov 15.I again during the night contacted Cell C sc \Legal Department"but to date still NO response from them.<br> I only use my PC for banking and e-mail purposes at home. I threatened to cancel the contract at Woodlands"